Short biographical treatments are provided in the following of three men, who are recognized as key engineers in three different fields: mechanical, electrical, and civil engineering. It is not unusual for engineering history, particularly that written by engineers, to consist of eulogies of individuals who have made a mark for themselves in their profession, and we tend to credit this kind of "great engineer" with the advance of the profession and the technology they worked with. They often started with little and became wealthy, the sort of rags-to-riches tale sometimes held up as an example for us to try to emulate.
However, in each of the following biographical stories there are interesting aspects of a more general nature to explore. The three "great engineers" in this little study are James Nasmyth, Guglielmo Marconi, and Robert Maillart, respectively, a mechanical, an electrical, and a civil engineer. In all three cases we can see that science is not synonymous with engineering, or that engineering is not merely, or even mainly, applied science, at least not in the early stages of that branch of engineering, and in most cases not in the mature stages either. All three careers show that a visual imagination is a key feature of the design process. There is often a relationship between engineering and art (i.e. the visual arts), but the relationship differs in different disciplines. Furthermore, there are significant differences in the preparation each man had for his career, partly typical of the differences between the type of engineering involved, and partly a result of the different locations and dates.
The bare chronology of the life of James Nasmyth is as follows (1)
|9||1817||Went to High-school Edinburgh|
|13||1821||Attended the School of Arts|
|21||1829||Went to London to Maudsley's|
|23||1831||Returned to Edinburgh to make my engineers tools|
|26||1834||Went to Manchester, to begin business|
|28||1836||Removed to Patricroft, and built the Bridgewater Foundry|
|31||1839||Invented the Steam Hammer|
|48||1856||Retired from business|
A conventional engineering biography of Nasmyth would certainly focus on the period he spent with Maudsley, who pioneered machine tool manufacturing and was known in his lifetime for the high quality and precision of his tools and the introduction of standardized screw threads which he promoted. The biography would go on to describe how Nasmyth built up a large business from practically nothing and invented the steam hammer, which Nasmyth himself considered his most notable achievement, subsequently using the hammer as his "coat of arms".
In a broader context, we can note that Nasmyth was active during a period of rapid industrialization of Britain, a period now called the Industrial Revolution. The first stage of that revolution was largely founded on water power. Water-powered industry, along with improvements to agriculture, increased the wealth of the country while making a large portion of the rural population surplus to the needs of agriculture but available for the expanding industry. The second stage of the revolution was set in motion when James Watt improved the steam engine so that it became a useful source of power in factories, rather than just at coal mines where cheap fuel was available and therefore the only sites for the earlier inefficient steam engines. Later, through the work of Trevethick and the Stephensons, the steam engine became a source of motive power in transport. James Nasmyth mentions in his autobiography that he saw James Watt (a Scot like Nasmyth) visiting James Nasmyth's father's house while James was a young lad. James Watt with his business partner Matthew Boulton, followed by Maudsley, and then Nasmyth, and many others like them, provided the engineering support for the burgeoning industries of nineteenth century Britain by supplying it with steam engines, looms, spinning machines, etc., and the machine tools with which to manufacture other machines. In this essay I propose to focus mainly on Nasmyth's education and training for what he did, and on the visual aspects of his way of working.
Nasmyth grew up before there was formal education in Britain in science subjects or in engineering, as we now know it, i.e. education through formal courses in post-secondary institutions like universities or higher technical colleges. That kind of system had by then been introduced in France and elsewhere on the continent of Europe, in Britain formal training took the form of apprenticeships, where the young man or his parents would pay a master in the trade a hefty premium or fee to pass on all the appropriate skills and knowledge to the young man over a set period of years. James Nasmyth, however, did not even serve that kind of apprenticeship. By the time he joined Maudsley he had effectively learned all that an apprentice would learn by observing and helping out in foundries and machine shops owned by fathers of his school friends and by learning from his own father who had a lathe and other tools, as well as from his own experiments and other efforts. He even operated a small brass foundry in his bed room. By the time he went to Maudsley in London he had distinguished himself by building model steam engines, making both models which worked and cutaway models which showed the inner mechanisms of the engines. These he gave or sold to Edinburgh University and several technical colleges, as well as to private individuals. Some of his engines were put to work powering small tools, much as small electric motors are used today. It was on the strength of one of these models and a set of engineering drawings that Maudsley took Nasmyth on as an assistant rather than apprentice.
Much of his knowledge obviously came from practice. In one key aspect of machine shop practice, the hardening and tempering of steel, on which the whole technology depended, Nasmyth describes how he learnt this from a skilled foreman, and how the process was as yet a mystery to science when the autobiography was written. It was not until the very end of the nineteenth century, after the development of the microscopy of metals, a scientific understanding of what goes on in heat treatment began to develop (3). While it is clear that Nasmyth did not complete a degree or diploma in science or engineering in the modern sense he did, however, attend some lecture courses in physics, mathematics, and chemistry at the University, in parallel with night courses at a technical college. His attendance at the university was facilitated by the professor in natural philosophy (physics) who was the recipient of a model steam engine from Nasmyth. However, other than his use of arithmetic and geometry in design, and possibly an appreciation of some concepts like fluid and gas pressure, there is no mention in Nasmyth's autobiography of any explicit use of science in his engineering work. On the other hand, this education, as well as his father's renown in painting, may well have been the key to the easy relationship he later had with scientists of his day, including Michael Faraday (Michael Faraday also acquired his professional skills and knowledge "on the job". He started his scientific career as lab assistant to his predecessor as professor at the Royal Institution, Humphry Davy.) , who received him when he first came to London and corresponded with him in later years.
James Nasmyth's father, Alexander, was a noted portrait and landscape artist, and James inherited and acquired some of his father's artistic skills which stood him in good stead in engineering. James Nasmyth also explicitly credits much of his success to his visual imagination, with which he was able to visualize mechanisms before putting his ideas on paper. All his working life he kept notebooks, which he called his "scheme books" (4). where his ideas took form as sketches before his designs were worked out in formal machine-shop drawings. Sketches were the prime vehicle and aid for his imagination while the formal drawings translated the ideas into precise guidance for machinists to follow. Until quite recently, at least until the 1950's, there was a considerable amount of time spent in engineering schools on training students in manual drafting and sketching. This has largely been displaced by computer-aided design and by analytical/mathematical courses. There is, however, now some concern that the visual faculty is a key element in engineering design and is being neglected too much. Not only is analysis no substitute for imagination in design, but an inability to visualize can lead to many problems including errors of judgement.
Nasmyth's key invention, the steam hammer, looks deceptively simple. Yet it was a considerable departure from the design of forge hammers in use at that time, which were modelled on their predecessor water powered hammers. The invention was clearly a visual exercise, which is how Nasmyth describes it. Nasmyth also mentions some of the ways the prototype was modified. The configuration of the steam hammer led Nasmyth to a new configuration of the steam engine, particularly suited to ships (5). These changes were primarily in the arrangement of components, not in any radical changes to the components themselves. This is still typical of what goes on in much engineering design (6).
The social context of Nasmyth's work is interesting, but particularly how little Nasmyth actually has to say about his own society while he was an adult. He makes some mention of the turbulent times his ancestors lived through in Scotland, and the role his grandfather played in the expansion of Edinburgh in the eighteenth century. There is also some reference to poverty in Scotland in his youth and the associated unrest and political concerns. When Nasmyth tours the Midlands of England during his second year in London, he does provide a graphic description of the desolation in the Black Country, a region devastated by mines and foundries, but when he describes his first machine shop in rented premises in Manchester, you have no inkling that this is the same town which prompted Engels, the son of a wealthy German industrialist and resident of Manchester only a few years later, to write from personal experience about the desperate conditions of the English working class, an experience which led Engels to become a close collaborator and financial supporter of Karl Marx, whose writings became the bible of communism.
After Nasmyth had established his own foundry and machine shops outside Manchester, where it grew to quite a large establishment with at least one hundred employees, he did have to contend with a strike. He broke this strike by bringing in new employees from Scotland to replace the strikers. Throughout all this section of his autobiography (7). he portrays himself as the benevolent employee, paying good wages and promoting employees on their ability. Most of Nasmyth's employees must have been skilled craftsmen who could advance their position in life through hard work and ability, as Nasmyth did, even if they did not end up wealthy (Skilled machinists like Nasmyth and many of his employees must have been in much the same situation in their time as skilled computer designers and software programmers are today in the "revolution" in information technology. They were in demand in the creation, implementation, and maintenance of the new technology, some of them becoming rich in the process. The ill effects were suffered by others, including those, like the mill workers of Nasmyth's time, who were employed in the new technology, but in routine jobs which required limited skills and provided low pay and no security.). This would not have been the case for the majority of the workers in textile mills, the biggest industry in Manchester. They had a different lot altogether. Some of these miserable labourers were children and many were women. Except for the narrow skill needed to tend a loom or spinning machine they had little or nor skill or education and no security, as there were plenty of others, including migrant Irish labour, to take their places. While the paternalistic Nasmyth built his new machine shops in what was then countryside and surrounded it with homes for his employees, the Manchester mill hands lived in congested slums, never sure of a job.
There is some indication in Nasmyth's book that the economy was not booming all the time in that he had to borrow money to patent the steam hammer (8). . Yet, you have no impression that the economy of Manchester went through several cycles of vicious boom and bust at that period, throwing thousands out of work in each bust. The explanation for this must be that Nasmyth's employees, as skilled tradesmen, had better conditions and prospects, as well as greater security than the lesser skilled mill hands. With a variety of tasks to tackle as the orders received by the company changed, Nasmyth's staff must have some variety of work and challenge. Having in his earlier years performed all the tasks they did, Nasmyth could on occasion work alongside his workers and he probably had a good relationship with his staff. This was not the case with most cotton mill owners, who seem to have treated the majority of their mill hands as expendable.
Nasmyth's business must have been affected by fluctuations of the economy of Manchester, but the fluctuations would have been moderated by his ability to get orders from elsewhere. Also, even in moderately hard times the owners of industrial establishments would have had to maintain and modernise equipment even when sales were down and half their employees were laid off.
When all the above considerations are taken into account, it is nevertheless odd to read an autobiography of a man who lived in the heart of England and not get any indication that this was a period when there was so much unrest in that region, including large numbers of people participating in marches on London and the notorious Peterloo Massacre (of protesting workers) in Manchester, which led many observers to think that a bloody revolution was likely (9).
Our second example of a great engineer is Guglielmo Marconi, who was born in 1874 and died in 1937. His father was a wealthy Italian silk merchant and his mother a member of a wealthy Irish/Scottish brewing and distilling family, the Jamesons. It appears that Guglielmo's education was patchy, not because he was poor, which he wasn't, and not because formal education was unavailable, but rather because his family was very well off which meant that they engaged private tutors but his mother tended to travel a great deal taking her sons with her, thereby interrupting their education. The result was that Guglielmo never completed any course leading to a diploma and did not qualify for university enrolment (10).
Marconi played with crude electrical experiments as a child, which led to access to the laboratory of a professor of physics at the University of Bologna, Augusto Righi, a neighbour of the Marconis. Through Professor Righi, Marconi also gained access to the university library. Righi was interested in the experiments of Heinrich Hertz who had demonstrated experimentally the existence of radio waves, then called Hertzian waves. When Hertz died in 1894 Righi wrote an appreciation of Hertz, which Marconi read, leading him to the idea of using these waves for wireless communication.
Despite Righi's opinion that this was a task for a trained scientist, Marconi started experiments on his parent's estate, first duplicating Hertz's work as others, including Righi, had done. Then he experimented in a variety of ways to extend the range of transmission and reception, mostly by trial and error, but including equipment developed by Righi and at least one device, the coherer detector, which had been developed by Edouard Branly, a professor in Paris, and which had also been used independently by Professor Oliver Lodge in England around 1890 (11). It would appear that much, if not all, that Marconi had done in his first two years of work on radio transmission was to improve on ideas of others, plus hit upon considerable improvements in antenna design. Furthermore, he seems to have focussed on what turned out to be lower frequencies, i.e. longer wave lengths, than was the case in the studies of Hertzian waves in most science laboratories at the time. Long waves travelled further than the short waves generated in the laboratories of that period.
In only two years the twenty-one year old Marconi was ready in 1896 to approach officialdom for support. The Italian authorities, however, were not interested, so Marconi's mother took him to London, where a relative got Marconi an introduction to the Engineer-in-Chief of the British Post Office, which was responsible for telecommunications in the U.K. Successful demonstrations of Marconi's system soon followed to the Post Office and the War Office upon which Marconi was launched on his career. Marconi's British relatives formed what was eventually called the "Marconi's Wireless Telegraph Company Limited".
Marconi was able during the next few years to set up several viable installations, mostly along the coast transmitting to light houses on islands, and for communication with ships. Telegraphy by wire was by this time well established on land as well as across oceans. Indeed telegraphy, and later telephony, by wire remained the preferred method for communication between major centres within and between countries until quite recently and has now received a new lease on life with fibre optics. Wireless communication had its first major market in communication involving at least one mobile station on land or at sea, and in communication with remote stations to which it would be expensive to lay a wire.
In 1901 Marconi claimed to have communicated from Cornwall in England to St. John's Newfoundland (This claim was doubted then and since, as the signals from Cornwall were only heard by Marconi and his assistant. There was no independent verification, However, two years later Marconi set up wireless communication between Cornwall and Glace Bay, on Cape Breton.). From then on the use of wireless telegraphy at sea grew rapidly, and a commercial transatlantic service opened in October 1907 (12). In 1909 Marconi was awarded the Nobel Prize in Physics, shared with C.F. Braun, and in 1910 his company paid a dividend for the first time (13). However, this is not a review of Marconi's career in conventional terms. The concern here is in the interplay of science and engineering in his work.
As noted already, Marconi did not complete formal training in either science or engineering. He did study science on his own, with some advice from at least one scientist, probably selecting only those subjects or even only portions of the subjects, which interested him. There is no mention in the biographies I have read that he studied much higher mathematics, though he must have covered the basics. One of the schools he did attend for a while is referred to as a Technical Institute (14). Apart from what may have been covered at this institute, which must have been the equivalent of a modern North American high school, there is no indication that he had any training in engineering. Indeed there is some indication of poor engineering in his early work. He had originally planned that his first transatlantic transmission would be from his station at Poldhu in Cornwall to a site on Cape Cod, Massachusetts. Sixty-one metre high antennas were erected at both sites. Before the transmissions could be tried both antennas were brought down by wind, the one at Cape Cod by only a stiff breeze. A simpler antenna was constructed in a hurry at Poldhu and Marconi resorted to using only a kite at St. John's., the closest point to England on this side of the Atlantic (15). If Marconi's structural engineering had been better, St. John's, Newfoundland might have missed the glory it acquired from Marconi! This kind of disregard of design practice or good technological practice is not unusual in people who have not benefitted from the rigours of engineering training and apprenticeship. In this Marconi was quite different from Nasmyth.
Wireless telegraphy was of course, firmly founded on science. The basic equations of electromagnetic radiation had been established by James Clerk Maxwell in 1865, and Heinrich Hertz produced experimental proof of this in 1888 (16). Other scientists worked on the phenomenon, including Oliver Lodge who anticipated some of Marconi's achievements, and Ambrose Fleming who later worked with Marconi. Lodge made several contributions to wireless transmission, including an improved detector and a method of tuning. However, he appears not to have realized the commercial possibilities of the technology at that stage, or was not inclined to pursue them vigorously. That is not surprising considering the mature state of telegraphy and telephony by wire, which was already big business by that time.
As far as Marconi's engineering was concerned, the relevant branch, electrical engineering, dealt at the end of nineteenth century largely with telegraphy by wire, electrical light and power and telephony. Some of the earliest electrical engineering was an extension of electrochemistry as electrical power came from galvanic batteries, and people like Michael Faraday worked on both chemistry and electrochemistry, as well as on electromagnetism. By the time Marconi was interested in electricity, this subject was a recognized branch of physics, to much the same extent as you will still find it in physics departments. It was not until the beginning of the twentieth century that electrical engineering was firmly established in universities as a subject separate from physics (In 1907 Dugald C. Jackson helped develop the first plan for a GE-MIT cooperative training programme in electrical engineering.). Up to that time the training of electrical engineers occurred in the electrical industries, which included many large companies by 1900.
Marconi's rivals in wireless telegraphy, including Telefunken in Germany, established much of the engineering which was special to this technology, in particular the practical design and production of many specific components. Marconi modified or scaled up much of this technology and operated initially much as an inventor does, following a practical goal - wireless communication - and focussing all his energies on achieving that. Once some success had been achieved the goal kept moving, i.e. towards reliable transmission over ever increasing distances. There is no question that Marconi made use of the science of electricity and magnetism, the science of electromagnetic waves. However, as far as the latter is concerned he would have been using the knowledge that electromagnetic waves existed, and knowledge of the equipment (i.e. technology) that scientists had used in their experiments. He also used the existing technology of electrical engineering, such as wires, insulation, bells, batteries, generators, condensers, coils, etc. The technology of wireless communication was a matter of finding the best combination of these parts, most of which already existed and had been used in other fields for some years. The laws established by science governed the effects produced, but although scientists like Lodge knew their science far better than Marconi did, they did not produce a commercially useful system, even though Lodge had already by 1894 produced equipment which worked in a laboratory. Indeed Lodge and his associates can be forgiven for not even seeing the potential of wireless communication, other than as a curiosity. Why should wireless communication be of value, when telegraphy by wire was already supported by a large industry and was reaching into every part of the country and spanned the globe?
Marconi's experiments followed ideas based on his imagination. On the technical side he must have had ideas on how electromagnetic waves are generated, reinforced, and focussed by antennae. On the business side he was able to see where there was at least one niche open for wireless communication, i.e. marine communication. He was also fortunate to have backers who did not need early financial returns from their investment.
As we know now, but Marconi could not have known before 1900, wireless telegraphy would not become truly viable until a means of electronic amplification had been developed. That depended on the diode vacuum tube rectifier and detector which Ambrose Fleming developed in 1905, and on the triode vacuum tube which deForest developed the following year.
Hugh Aitken has addressed the question of the interplay of science and technology in the development of wireless telegraphy. The following is mostly taken from his book dealing with the contributions of Hertz, Lodge, and Marconi, with also some reference to Maxwell (17).
James Clerk Maxwell provided the initial mathematical theory for electromagnetic radiation. Both Heinrich Hertz and Oliver Lodge discovered, independently of each other, empirical ways of testing Maxwell's model, developing ways of producing radio waves and detecting them. Of course, both the theoretical postulates about electromagnetic radiation and the discovery of ways to produce and detect in the laboratory the type of electromagnetic radiation we now call radio waves were prerequisites for the development of practical radio. It therefore seems that pure science, the knowledge about electromagnetic radiation as it was about 1890 was the source and origin of radio. Once this knowledge existed, someone would eventually think of a practical use for it - a case of technology following science.
However, in this development we can see that technology also has a role in science, that much of science depends on pre-existing technology. The invention and development of equipment is technology, the equipment itself and its use are aspects of technology, in much the same way as the development of a sewing machine or bicycle is a technology. The design of such equipment involves important choices which are not dictated by scientific laws. The choices made in designing equipment and procedures may all be in accord with science, but are unlikely to be all equally good (This is the kind of question Ferguson deals with in op cit, and can be understood more clearly when we consider the great variety in design for such items as a bicycle, all of which satisfy the laws of mechanics and the strength of materials. Also, it took a lot of intuition and trial and error to make use of Ohm's and Stefan's Laws to produce a light bulb, which was not an obvious application of these laws before the event.). It was therefore quite possible for Marconi, who did not have formal scientific training and experience, and was a mere twenty year old, to come up with better designs than Lodge a well-known professor of physics. Whether Marconi did this by judgement, intuition, or merely by trial and error, is not the main issue. He may have followed notions about the phenomena concerned and notions about the processes in the equipment which were quite simple, even erroneous from the point of view of expert scientists in the field. Bad science, or popular but incomplete or erroneous ideas on the laws of nature and other scientific matters may well be used by inventors in their inventions and yet achieve enough to encourage design changes and further tests. Often it is only when a device works that the science involved is fully investigated and understood.
The existence of scientific knowledge is also no guarantee that its practical application is evident. It took about thirty years for Maxwell's equations to lead to the beginnings of radio.
The key feature in Marconi's early work was not that he could see the economic value of radio as we know it. It is more likely that he saw in Hertzian waves a possibility of filling a commercial niche which telegraphy by wire could not fill. He had no interest at that time in broadcasting as we know it. That would have been very far fetched then. The use he would have had in mind for radio can only have been the sending of telegrams by wireless, using morse code.
Science comes into the picture in technology in a different way once the possible viability of the technology is established. Once experiments started with a clear aim of commercially exploiting wireless telegraphy, the interest of some scientists shifted from simply studying the phenomenon for its own sake to studying what went on in the commercial equipment, e.g. in the circuits and components developed in the technology, such as spark gaps, tuned circuits of coils and condensers, and in and around antennas. Theories were formulated and experiments conducted with this in mind. Changes were made to the equipment, using systematic studies or pure guess work in any way that seemed likely to improve them, and so the equipment was improved. Often this would have been a case of technology leading science. One important example of this was the discovery by Marconi that radio waves of low frequency, i.e. long waves, can follow the curvature of the earth. Until then it had been assumed by scientists and by Marconi that radio waves, like light, can only be transmitted between points visible by light from each other, i.e. line-of-sight transmission, as is the case with very high frequency (very short wavelength) waves. Marconi just happened to experiment with the longer wave lengths, while physicists tended to study very high frequency transmissions, for which the equipment needed was more compact and could be contained in a laboratory In the 1920's Marconi did turn his attention to radio at very high frequencies for line of sight communication, after amateurs had already established the usefulness of short waves. (Aitken, p 272).).
In much of Marconi's work he was not the one to get the idea for the equipment or technique. The dipole oscillator, morse code key, the coherer and the antennae he used in his first demonstration equipment in England were all based on other men's ideas (18). However, individually and in combination Marconi's versions were more effective than previous models. Marconi improved the design rather than develop radically new ideas. According to Aitken, Marconi excelled in "the indispensable process of critical revision" (19). He usually only claimed in patents and other statements to have produced new "improvements". The one area of invention/design in which Marconi excelled seems to have been in antenna design, i.e. in formulating ideas for the arrangement of wires and circuits, not the structural engineering involved. He seems to have been the first to introduce of the ground-plane, or grounded vertical, antenna for radio transmission and reception (20) , and he was to pioneer several other antenna designs over the years.
I haven't had access to any source documenting how Marconi arrived at his "improvements", though it is hard to imagine that it was a process involving only numbers and equations. As an experimenter, working with equipment, he must have had ideas in a visual form, seeing in his mind whatever he thought was going on in the equipment. His near contemporary, Nikola Tesla (1856-1943) was well known in Europe and North America as an electrical engineer in alternating current when the young Marconi arrived in London, England. He too became greatly interested in wireless transmission of electromagnetic radiation and his writing show that his lively imagination was very much visual, even to the extent of his having dreams and visions on these matters (21) (Tesla, like Lodge, demonstrated in lecture rooms the transmission of Hertzian waves before Marconi arrived in England. Tesla, however, since he was then primarily interested in electrical power generation and transmission, seems to have been focussed on the possibility of transmitting power this way, not weak signals in Morse code.) It is also of interest that James Clerk Maxwell, whose theory is of electromagnetic radiation is expressed in the form of equations, tended to use mechanical analogies in much of his work, including actual mechanical models, such as one he constructed with gears and rotating masses forming and analogy for two inductively coupled circuits (22).
Our third "great engineer", is probably the least well known of the three featured here (Most engineers today have probably not heard of James Nasmyth, but he was obviously well known in his day, even to the general educated public, judging by the publication of his autobiography by a major publisher.). Robert Maillart may not be known to most contemporary civil engineers, even though many of his structures are still standing and are obviously modern in spirit and material. His work has however, evoked some interest outside engineering circles, notably the visual arts community, not because he drew or painted well, as many engineers do, but because his engineering work is of the kind sometimes considered to be a form of art.
Robert Maillart was born in 1872, i.e. two years before Marconi. He is the only one of our three examples to have completed a standard university degree programme in engineering.His chosen field of engineering, civil engineering was well established and he studied it formally for four years, graduating in 1894 from the Federal Technical Institute of Zurich. His first job was on railway design with an engineering firm; he then went on to road and bridge design with the City of Zurich. In 1902 he founded his own company of design consultants and builders in reinforced concrete. Maillart happened to be stuck in Russia during the First World war. When he returned to Switzerland he had to start again, this time focussing as a consultant only on design, not on construction.
Maillart's university education in structural design was primarily under Ritter, a recognized expert in reinforced concrete design who had developed several principles of design in this medium. One of these principles was the value of calculations based on simple analyses, using appropriate assumptions based on common sense, i.e. it was not necessary to attempt to use complete but complex mathematical theory, a procedure others tended to favour at that time but which could only be applied to bridge components with certain standard shapes. A second principle was the careful consideration of the construction process, not just the final product. The third principle was that the structure be tested by full-scale load tests. This again was in opposition to those who put their faith in mathematical calculations. All these principles were not really radical departures from previous practice, only a judicious blend or adaption of available techniques with, however, a strong emphasis on careful study of the built structures to learn from them.
In all practical engineering design there is a certain tension between pure theory and practice, which is not likely to be always evident to the student, since all the rules and procedures covered in textbooks will appear to be based on science as the last word in the matter at hand, and it may appear that all engineering is based on science. However, Europe is full of large buildings, which were designed and built centuries ago without any theoretical basis as we know it, i.e. while we must presume that the builders will have evolved certain rules to follow there was with no analysis of stresses and strains. Of course, we only see now the structures which have remained standing. There were numerous instances of collapses during and after construction, so the elegance of, say, the gothic cathedrals was achieved by a combination of daring and trial and error, with a great deal of loss of life and material. The knowledge used in the form of rules for design and construction were arrived at empirically. Any formulae on the relationships between components, the shape of arches, etc would have been distillations of experience and not based on science (The word "science" means knowledge so it could be applied to any knowledge, including rules derived from experience. However, here I use it in the more restricted sense of knowledge derived by scientists, through theory or experiment which elucidate fundamental relationships.(The nature of science is a topic for a separate paper).). The theory of stresses in structures only reached something like a sound footing in the nineteenth century, though work of a mathematical nature started in the seventeenth century. Current mathematical theory of structures is quite complex and requires modern computing techniques to apply to anything but the simplest practical structures. The early theories of structures were usually crude, even wrong in some particulars although they appeared to fit reality. Most, if not all, application of mathematical analysis to structures, including modern finite element methods, involve some compromises, some simplifying assumptions. Designs based on theory often worked because a generous margin of safety was included and the rules followed could be modified as a result of experience. In Ritter's and Maillart's time, German engineers and scientists had developed elaborate mathematical techniques and were so confident that they saw little need for practical load tests of designs developed using these techniques, while other engineers preferred to let their designs evolve from previously successful designs.
A virtue of Ritter's principles was that they encouraged designers to think of shapes and forms which could not readily be analyzed completely using available mathematical techniques. Designers were free to use their imagination and intuition, as Maillart evidently did. While he used, as all designers do, elements of design previously used by others, such as the box girder developed in iron by Thomas Telford a century before, he developed a daring and eloquence suited to and exploiting reinforced concrete. An interesting aspect of his work is that when one of his early bridges developed cracks in walls near the abutments, he simply left out that part of the structure in the next bridge design. In this instance he was able to conclude from examining the bridge with cracks that the cracks were not so much a sign of weakness but rather of unnecessary stiffness at that location! In much of his work we see a steady simplification of form. Elegance through simple forms became a goal for him. None of the forms he chose on this basis could be predicted through the mathematical theory then in vogue. Theory could not be used to produce a shape, nor to predict how that shape might work, only analyze a structural shape which has already been conceived, and to analyze how that shape might behave under assumed conditions.
Maillart's bridges are of interest in that it is possible for us to intuitively analyze the structures though when they were built he was often attacked by academics who focussed on theoretical research (24). The form makes sense. In effect the sense, as the well as the evident simplicity and economy, is a part of the beauty of the structure. It does not require technical knowledge to recognize this beauty and sense, and the shapes involved appeal readily as art, in the same way as sculpture does. Bridges of this sort are perhaps the only large engineering artifacts recognized as an art form. Pictures of Maillart's bridges have been exhibited in galleries as art (the bridges themselves are the pieces of art, not the pictures).
Many commentators are interested in the way the structural engineering of bridges can produce art, which is a combination of high technique and style. In the present context, Maillart's work provides clear evidence of the role of visual imagination in engineering. With visual imagination governing the design concept, it is natural that one individual, the chief engineer with the vision, gets most of the credit for the design. Bridge design has retained this feature, perhaps because this type of engineering, indeed most civil engineering, is not mass production. Also bridges are often public property and the chief design engineer for a bridge is not always subordinate to an architect or manager, which is now seldom the case with the construction of major buildings and many other engineering activities.
While Maillart was contemporary with Marconi, living at the end of an era of "Great Engineers", bridge design has continued to be a field in which individual engineers get the main credit.
Three examples have been presented of prominent engineers. Only one of them, Maillart, received full formal training in the modern sense as in engineering, and he is probably the one of the three who was least known in his own time, or later. Another, Marconi, shared a Nobel prize in physics, although he had no formal qualifications in physics, and may not have actually made any scientifically remarkable discoveries, at least not in the way most science is done. His achievements, which were considerable, were mainly technological, i.e. had more to do with the design of equipment and systems, and little to do with discovery of laws of nature. However, Nobel prizes are not awarded in engineering, so the judges may have had to bend the rules in order to acknowledge Marconi in this way.
Marconi and Maillart were contemporaries. Our third example, Nasmyth, lived before the other two. He exemplifies the largely self-taught pioneer British engineer of the Industrial Revolution. He also exemplifies a formal connection between art and engineering which was evident in many engineers in the nineteenth century. Interestingly, Samuel Morse, a key developer of telegraphy, i.e. a developer of some of the technology Marconi used, was a portrait artist by training and profession prior to getting into telegraphy. I know of no evidence that Marconi had artistic leanings in the conventional sense, but there is no reason to doubt that he did not visualize rather than use mathematics or other formal ways of thinking, since he had little training in mathematics. Marconi's work is however an interesting case study in the interplay between science and technology, and an example of forces other than science driving a technology based on a scientific discovery.